ETS-Lindgren HI-1801 Microwave Oven Survey Meter - Manual (Page 7)

Introduction | 7
1.0 Introduction
The ETS-Lindgren Model HI-1801 Microwave Survey Meter is a rugged,
compact, portable instrument that is virtually immune to failure caused by
excessive fields or physical abuse. This instrument is acceptable to the US
Government Center for Devices and Radiological Health (FDA/CDRH) and to all
major microwave oven manufacturers for testing ovens in use and after repair.
This easy to use meter, and the step-by-step instructions in this manual will
enable you to easily and accurately measure leakage from your microwave oven.
Microwave leakage (electromagnetic fields) is detected by an array of eight hot
carrier diodes housed in the large end of the plastic probe. This antenna array
has the unique feature of being able to sum microwave electric fields of any
polarization in a plane perpendicular to the axis of the probe. The antenna lobe
(effective measuring area) is also very broad, making the instrument easy to use
when measuring leakage around an oven door. The spacer cone is designed to
provide 5 cm spacing from the tip of the probe to the center of the array.
Each detection probe and meter amplifier is calibrated as a unit and serves all
three ranges: 2, 10 and 100 mW/cm². Only the 2 and 10 mW/cm² ranges are
considered compliance ranges in terms of compliance with the DHHs/CDRH
standard for microwave survey instruments contained in CFR 1030.10.
The HI-1801 must be used with the spacer cone in place. Using the
instrument without the cone will result in reading errors and may
damage the unit.
Calibration Method
Each meter is calibrated by placing the probe in a CW (continuous wave)
2450 MHz electromagnetic field generated by a crystal controlled solid state
source. The source feeds an anechoic chamber through a section of waveguide
terminating in a slot radiator. Calibration is performed at a level of 1 mW/cm² and
a standard temperature of 75º F.